1. Field Of The Invention
The present invention relates to downhole oil and gas well tools and more particularly relates to a jacking apparatus that can be used in a downhole oil well environment when supported upon the free end of a length of coil tubing that is wound upon a spool at the wellhead area. Even more particularly, the present invention relates to an improved downhole oil well tool that can be used to remove objects that are stuck in the oil well by generating a lifting or jacking force through pressurized fluid applied to a piston after slips or wedges anchor the tool body to the wall of a casing so that the lifting energy is transmitted to the casing rather than solely to the coil tubing unit.
2. General Background
In the drilling and production of oil and gas wells, it is often a problem to complete a well because an object such as a downhole oil well tool or instrument has become stuck in the well. Once these objects are stuck, they often require considerable force for removal. This a is problem in restricted environments wherein the well bore is very small in diameter. Often times, a coil tubing unit can be used to reach restricted portions of a well. However, the lifting power of a coil tubing unit is somewhat restricted because of the small diameter (and small wall thickness) of coil tubing.